Dang!
Hummers suck for everything IMO.....can't tow much, can't haul people or stuff, and the gas mileage sucks.
If you're towing a boat that weighs 10K, it would seem you would also be hauling the gang and all their stuff.......get a Suburban. Wish they could be had with a Duramax...I'd be at the dealer tomorrow.
We had a Yukon XL(GMC's Suburban) and it wouldn't do the job. We had to trade it for a dually.